It is desirable in a trailer that the payload be placed in an area where the load distribution on the tractor-trailer axles is optimized. This means that the load must often be placed towards the center of the trailer when the vehicle is not fully loaded.
Heretofore, shoring bars have been used at the front and rear ends of the load to maintain the load at the desired location. When high density loads are involved, the shoring bars are generally not strong enough to restrain the load when the trailer is braked. In addition to not adequately restraining the load, the forces developed are transmitted directly to local areas of the side walls or other relatively weak structures not built to withstand high load forces. One such high density load, for example, may involve stacks of beer containers. The relatively low friction between the containers cause higher than normal forces to be exerted during a braking operation building up excess stresses in the shoring bars and other parts of the trailer.
While high density loads are important, low density loads must also be considered. For example, maximum space for carrying the low density load is desirable. Consequently, it is necessary that the problems relating to forces caused by high density loads be solved without sacrificing the space requirements for low density loads.